Formable aquatic coverings for preventing biofouling

ABSTRACT

The instant invention describes an anti-biofouling structure for placement onto structures or surfaces that are exposed to aquatic environments. Embedded within the anti-biofouling structure are agents that can diffuse out of the structure and prevent the formation and/or accumulation of plant and animal species build-up that creates biofouling. The instant invention also describes a system for preventing biofouling of an object stored in an aquatic environment which includes the anti-biofouling structure, and a protective cover element constructed and arranged to fit various structures, such as boat propellers.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. 119(e) to the U.S.Provisional Application No. 61/361,725, entitled “Formable AquaticCoverings for Preventing Biofouling” filed Jul. 6, 2010, the contents ofwhich are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to the protection of structures fromdamage as a result of continuous exposure to aquatic environments; moreparticularly to devices which attach to submerged structures, therebypreventing formation of biofouling; and even more particularly to asystem for preventing aquatic biofouling containing a propellerenclosure and a formable and disposable propeller glove havinganti-aquatic biofouling properties.

BACKGROUND OF THE INVENTION

The growth and attachment of various marine organisms on structures inaquatic environments, known as biofouling, is a significant problem fornumerous industries, including the boating and shipping industry, theoil and gas industry, and the fishing industry. Most surfaces, such asthose associated with boat hulls, underwater cables, oil rig platforms,buoys, and fishing nets, which are exposed to coastal, harbor or oceanwaters eventually become colonized by animal species, such as barnacles,mussels, bryozoans, hydroids, tunicates, tubeworms, sea squirts, andvarious plant species. Biofouling results from the interaction ofpolymeric adhesives produced by the plant and animal species with thesubstrates for which they are attached. Despite the appearance ofsimplicity, the process of biofouling is actually complex and involvesnumerous interactions with many types of microorganisms andmacroorganisms.

While biofouling creates ecological problems by distributing nativeplant and animal species to non-native environments, its economiceffects are of greater concern. Large amounts of biofouling on shipsresult in corrosion of the surfaces and the eventual deterioration ofthe ship. Large amounts of macroorganisms build-up also causes increasesin the roughness of the ship's surface such that the ship experiencesgreater frictional resistance, decreased maneuverability, and increaseddrag, resulting in increased fuel consumption. Recreational boaterssuffer from the same problems, as barnacles and other animals attach topropellers submerged in water. Navigational buoys or pier postscontaining surfaces with large amounts of biofouling are subjected toincreased stress resulting from increased weight. This increased stressoften results in decreasing the useful life of the structures andnecessitating continuous replacement.

Various methods have been used in reducing biofouling build-up. One ofthe more common methods, particularly in the boating and shippingindustry, is scraping. However, scraping is labor intensive andenvironmental issues have been raised over the concerns that scrapingresults in the increased spread of invasive species. Therefore, thereexists a need for devices that eliminate or reduce the amount ofbiofouling of surfaces exposed to water.

DESCRIPTION OF THE PRIOR ART

One strategy for protecting objects in contact with water and preventingaquatic biofouling includes the use of physical coverings. Thesecoverings act as protective devices by shielding or separating thestructures from the water. For example, U.S. Pat. No. 3,220,374discloses a marine protective device. The invention is directed towardsa unique means and method of protecting marine equipment from thecorrosive action of the water and/or marine growth when the boat is notin use.

U.S. Pat. No. 3,587,508 discloses an outdrive protective apparatus foreasy attachment to a boat. The apparatus protects the outdrive of aninboard-outboard motor from marine growth when the boat is not in use. Abag is placed around the outdrive unit for easy attachment to thetransom of a boat in a manner which provides a watertight seal betweenthe bag and the transom and around the outdrive unit.

U.S. Pat. No. 3,870,875 discloses a cover for covering the propeller andrear drive assembly of an outboard-inboard motor boat. The cover has anelectric taillight mounted to the rear of the cover and which can beelectrically connected to the taillight wire of a boat trailer when theboat is mounted on the boat trailer for towing on a roadway. The lightserves as a warning to motorists approaching the boat and boat trailerfrom the rear.

U.S. Pat. No. 4,998,496 discloses a shroud for a marine propulsionsystem which includes a waterproof shroud body that can be fastened tothe transom of a boat to surround the outboard portion of the propulsionsystem. Locking and sealing mechanisms secure the shroud to the boattransom in water-tight engagement and a submersible pump is operable toremove water from the shroud body so that the propulsion system iseffectively in dry dock.

U.S. Pat. No. 5,072,683 discloses a drainable protective boat motor bagapparatus including a boot defining a bag for fitting over the propellerand stem of an outdrive of a motor mounted on the stern of a boat. Thebag includes a channel extending from the mouth to the closed end of thebag for receipt of an open ended hose such that, once the bag has beenpositioned over the stem, a hose may be inserted for pumping of residualfrom such bag. A tie string may be incorporated around the mouth of thebag for tying it to the stem and, if desirable, a separate protectivesack may be included for covering the propeller blades to protect themfrom direct exposure to the bag itself.

U.S. Pat. No. 5,315,949 discloses an apparatus for protectively coveringa motor prop of a boat. The cover includes an adjustable collar, aflexible, opaque bag, and an adjustable collar draw line. The bag has anopen top end attached to the collar. A closed bottom end of the bag isopposed to the top end, and has a weight attached thereto. Theadjustable collar draw line of the collar is such that with the bagplaced over the outcropping, the open end of the bag may be closedaround the outcropping by pulling the adjustable collar draw line. Thecollar includes a locking slot for locking the adjustable collar drawline in place around the outcropping. A manipulation handle removablyattaches to the collar for facilitating the placement and removal of thecover onto and off of the outcropping. With the cover in place over theoutcropping, water and light are prevented from entering the interior ofthe bag, whereby water borne life forms such as filter feeding creaturesand plant life cannot thrive within the cover. As such, the motor propis kept virtually free of water borne life forms while the motor prop iscovered.

U.S. Pat. No. 6,152,064 discloses a protective propeller cover. Thecover includes a flexible sleeve into which buoyant material is placedto provide a buoyant enclosure. A flexible propeller cover portion issecured to the flexible sleeve, and the end of the cover is releasablysecured about the propeller. The buoyant enclosure is positionedadjacent to the propeller and extends above the water line when thepropeller is positioned beneath the water line. The buoyant enclosureserves to protect swimmers from direct contact with the propeller whenswimming in proximity to the boat. The protective propeller coverapparatus further serves to protect the propeller during transport orstorage. The protective propeller cover apparatus further serves as ananchor cover when the boat is underway. The protective propeller coverapparatus further serves as an emergency flotation device.

U.S. Pat. No. 6,609,938 discloses a propeller protector slipper which isused on inboard and outboard motors of boats that are anchored,drifting, aground, docked, in storage, or out of water in transit. Thepropeller protector slipper ensures protection for the propeller fromelements that cause pitting and damage to the propeller, as well asminimizing propeller related injuries. The protector propeller slipperalso provides a gage for projecting the distance of the propeller of atrailered boat from a following vehicle.

U.S. Publication No. 2008/0020657 discloses an apparatus for protectingthe out-drive of a watercraft. The apparatus comprises a locating memberadapted for attachment to the underside of the marlin board of thewatercraft and a shroud engageable with the locating member to providean enclosure about the outdrive. The shroud is buoyant and can befloated into sliding engagement with the locating member. The shroud hasan opening which is closed upon engagement of the shroud with thetransom of the watercraft to preventingress of water into the interiorof the shroud. A connection means and the locking means are provided forreleasably connecting the shroud to the locating member.

In addition to the use of physical coverings as illustrated above, otherstrategies have been employed in efforts to reduce biofouling. U.S.Publication No. 2009/0185867 discloses a system and method for reducingvortex-induced vibration and drag about a marine element. The systemincludes, but is not limited to, a shell rotatably mounted about themarine element, the shell having opposing edges defining a longitudinalgap configured to allow the shell to snap around at least a portion ofthe marine element. A fin can be positioned along each opposing edge ofthe longitudinal gap, wherein each fin can extend outwardly from theshell. The fins can be positioned on the shell so as to reducevortex-induced vibration and minimize drag on the marine element. One ormore antifouling agents can be disposed on, in, or about at least aportion of the shell, the fins, or a combination thereof.

U.S. Pat. No. 7,390,560 discloses a coating system for defouling asubstrate. The system includes a ship hull, immersed in water orseawater for long periods of time. The system comprises a conductivelayer, an antifouling layer and a means for providing an energy pulse tothe conductive layer. The conductive layer comprises polymers, such ascarbon filled polyethylene, which are electrically conductive. Theantifouling layer comprises polymers, such as polydimethylsiloxane,which have a low surface free energy. The layers are designed such thatwhen the conductive layer is exposed to a pulse of electrical, acousticor microwave energy or combinations thereof; said conductive layerseparates from said antifouling layer.

SUMMARY OF THE INVENTION

The instant invention describes an anti-biofouling structure forplacement onto structures or surfaces that are exposed to aquaticenvironments. Embedded within the anti-biofouling structure are agentsthat can diffuse out of the structure and prevent the formation and/oraccumulation of plant and animal species. In a particular embodiment,the anti-biofouling structure covers the blades of a boat propeller.Embedded within this structure is the anti-biofouling agent sirolimus.The instant invention also describes a system for preventing biofoulingof an object stored in an aquatic environment. The system includes theanti-biofouling structure and a protective cover element constructed andarranged to fit various objects, such as a boat propeller.

In one embodiment, the instant invention describes an anti-biofoulingstructure for placement onto an object exposed to aquatic environmentscomprising a formable covering material for securing to an object whichis in contact with an aquatic environment. The formable coveringmaterial comprises at least one anti-biofouling agent, whereby securingof the object with said material results in preventing the formation ofbiofouling along the surface of the object. The instant invention alsodescribes a system for preventing biofouling of objects which areexposed to aquatic environments comprising a cover having a materialcontaining one or more anti-biofouling agents. The cover has a frontsurface, an expandable body portion which is traversable between a firstposition and a second expanded position, an interior portion sized andshaped to enclose an object which is exposed to aquatic environments,and one or more securing members for securing said cover to said object.The system also includes a formable covering material for securing to anobject which is in contact with an aquatic environment. The formablecovering material comprises at least one anti-biofouling agent, wherebysecuring of the object with said material results in preventing theformation of biofouling along the surface of the object.

In an alternative embodiment, the system includes a first rigid membermade of a material containing one or more anti-biofouling materialshingedly securable to a second rigid member. The second rigid member ismade of a material containing one or more anti-biofouling agents. Eachof the rigid members contains an interior which is sized and shaped toreceive an object which is exposed to an aquatic environment. The coverfurther includes one or more securing members for securing the cover tothe object. The system also includes a formable covering material forsecuring to an object which is in contact with an aquatic environment.The formable covering material comprises at least one anti-biofoulingagent, whereby securing of the object with said material results inpreventing the formation of biofouling along the surface of the object.

In another alternative embodiment, the system for preventing biofoulingof objects which are exposed to aquatic environments comprises aflexible cover containing one or more anti-biofouling materials. Thecover contains a first face partially connected to a second face and aninterior portion sized and shaped to receive a boat propeller. Thesecond face contains a slitted portion terminating in an opening whichis sized and shaped to receive a shaft of the propeller. The first faceand the second face contain a first member of a hook and loop fastenersecuring system. The system further includes a strap containing a secondmember of a hook and loop fastener securing system. The strap is sizedand shaped to secure to the first member of a hook and loop fastenersecuring system.

Accordingly, it is a primary objective of the instant invention toprovide an anti-biofouling structure which prevents the formation ofbiofouling on an object which is exposed to an aquatic environment.

It is a further objective of the instant invention to provide ananti-biofouling structure which contains anti-fouling agent dispensingstrips.

It is yet another objective of the instant invention to provide ananti-biofouling structure which contains anti-fouling agents withinreservoirs and/or are microencapsulated.

It is a still further objective of the invention to provide ananti-biofouling structure in which the anti-fouling agent is sirolimus.

It is a further objective of the instant invention to provide a systemfor preventing biofouling of an object stored in an aquatic environmentwhich includes an anti-biofouling structure and a protective enclosureelement.

Other objects and advantages of this invention will become apparent fromthe following description taken in conjunction with any accompanyingdrawings wherein are set forth, by way of illustration and example,certain embodiments of this invention. Any drawings contained hereinconstitute a part of this specification and include exemplaryembodiments of the present invention and illustrate various objects andfeatures thereof.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a simplified illustration of a typical boat propeller system;

FIG. 2 illustrates a particular embodiment of the anti-biofoulingstructure of the instant invention;

FIG. 3 illustrates placement of the anti-biofouling structure to thepropellers and propeller shaft;

FIG. 4 illustrates the anti-biofouling structure in the form of a rolledup sheet;

FIG. 5 illustrates a general schematic of an oil rig used to excavateoil reserves in deep waters with the anti-biofouling structure attachedto a portion of the rig;

FIG. 6 illustrates the use of the anti-biofouling structure with a buoy;

FIG. 7A illustrates a particular embodiment of the anti-biofoulingstructure in which the diagonally arranged horizontal and verticalelements contain anti-fouling agent dispensing strips;

FIG. 7B illustrates a particular embodiment of the anti-biofoulingstructure in which the diagonally arranged horizontal and verticalelements contain anti-fouling agents within reservoirs and/or aremicroencapsulated;

FIG. 8A illustrates a particular embodiment of the anti-biofoulingstructure in which the horizontal and vertical elements containanti-fouling agent dispensing strips;

FIG. 8B illustrates a particular embodiment of the anti-biofoulingstructure in which the horizontal and vertical elements containanti-fouling agents within reservoirs and/or are microencapsulated;

FIG. 9 illustrates a particular embodiment of the protective enclosureelement in the form of an expandable bag propeller cover;

FIG. 10 illustrates the protective enclosure element in an expandedposition;

FIG. 11 illustrates an alternative embodiment of the protectiveenclosure element;

FIG. 12 is a perspective view of the back end of the extended protectiveenclosure element;

FIG. 13 illustrates the protective enclosure element with a stiffeningplate;

FIG. 14 is a frontal view of the protective enclosure element positionedover a boat propeller;

FIG. 15 illustrates the protective enclosure element positioned over aboat propeller and secured to the boat propeller shaft;

FIG. 16 illustrates both the protective enclosure element positionedover a boat propeller and secured to the boat propeller shaft and theanti-biofouling structure positioned on the blades of the boatpropeller;

FIG. 17 illustrates a front view of an alternative embodiment of theanti-biofouling structure in the form of a claim shell configuration;

FIG. 18 is a rear view of the alternative embodiment of the biofoulingstructure illustrated in FIG. 17;

FIG. 19 is a perspective view of the embodiment of the biofoulingstructure illustrated in FIG. 17, illustrating the components of theclamshell;

FIG. 20 is a side perspective view of the alternative embodiment of theanti-biofouling structure;

FIG. 21 is a rear perspective view of the alternative embodiment of theanti-biofouling structure shown in FIG. 20;

FIG. 22 is a rear perspective view of the alternative embodiment of theanti-biofouling structure shown in FIG. 20, illustrating the structurein a closed, sealed configuration;

FIG. 23 is a side view of an alternative embodiment of theanti-biofouling structure in the form of collapsible bag-likeconfiguration;

FIG. 24 is a side view of the embodiment of the anti-biofoulingstructure shown in FIG. 23, illustrating the bag in a closed, sealedconfiguration;

FIG. 25 is a side view of the anti-biofouling structure shown in FIG.24, illustrating the bag being removed from covering of a propeller.

DETAILED DESCRIPTION OF THE INVENTION

While the present invention is susceptible of embodiment in variousforms, there is shown in the drawings and will hereinafter be describeda presently preferred, albeit not limiting, embodiment with theunderstanding that the present disclosure is to be considered anexemplification of the present invention and is not intended to limitthe invention to the specific embodiments illustrated.

The instant invention describes an anti-biofouling structure forplacement onto structures or surfaces that are exposed to aquaticenvironments. While the anti-biofouling structure will be described inthe specification as being useful on a boat propeller, one of skill inthe art would recognize that the anti-biofouling structure is notlimited to boat propellers and may be applied to numerous otherstructures placed in aquatic environments, such as but not limited topier posts, buoys, oil rig structures, boat docks, and the like.Accordingly, FIG. 1 is a simplified illustration of a typical boatpropeller 10 having a motor drive system 12. Attached to the hub 14 aremultiple propeller blades 16. A shaft 18, which interconnects the hub 14to the outboard motor drive system 12, provides a mechanism forrotational movement of the propeller blades 16.

FIG. 2 illustrates a particular embodiment of the anti-biofoulingstructure 20 in the form of a boat propeller sock. The boat propellersock 20 has a first end 22 and a second end 24. The boat propeller sock20 is placed on the propeller 16 by inserting the distal end 16 a ofpropeller 16 into the first end 22 of the boat propeller sock 20 throughopening 26. As the boat propeller sock 20 is positioned over thepropeller 16, the boat propeller sock 20 is aligned such that the firstend 22 rests at or near the proximal portion 16 b of the propeller 16and the second end 24 of the boat propeller sock 20 rests at or near thedistal portion 16 a of the propeller 16. In order to fit securely, theboat propeller sock 20 can be constructed to include the same generalcontoured shape as the propeller. FIG. 3 illustrates placement of theboat propeller sock 20 on the multiple propeller blades 16.

While the instant invention has been described in the form of a boatpropeller sock, the anti-biofouling structure 20 can be shaped to fitany structure. FIG. 4 illustrates the anti-biofouling structure 20 inthe form of a rolled up sheet. As such, the anti-biofouling structure 20can be placed onto various types of aquatic structures, such as netting,in-take pipes, and sewage pipes. FIG. 5 illustrates a general schematicof an oil rig used to excavate oil reserves in deep waters. The oil rig28 sits above ocean water 30. Support columns 32 and 34 terminate atbases 36 and 38, respectively, resting at the ground level 40 below theocean surface. To extend the life of the support and base structures,the anti-biofouling structure 20 can be either embedded within or, asillustrated, simply wrapped around the support column and base. FIG. 6illustrates the use of the anti-biofouling structure 20 with a buoy 42.The anti-biofouling structure 20 can be attached to the portion of thebuoy that is near or in direct contact with the aquatic environment toprevent the accumulation of biofouling within those areas. Additionally,anti-biofouling structure 20 can be attached to any of the cables 46which anchor the buoy 42 to the sea floor.

FIGS. 7A, 7B, 8A, and 8B, illustrate particular embodiments of theanti-biofouling structure 20 which comprise a lattice-like or fenestratearrangement. Alternatively, biofouling structure 20 may be in the formof a mesh. The anti-biofouling structure 20 contains a plurality ofhorizontally positioned elements 50 interweaved with a plurality ofvertically positioned elements 52. Both the horizontally positionedelements and the vertically positioned elements may be arrangeddiagonally, thus forming a crisscross pattern, see FIGS. 7A and 7B, oralternatively in a parallel fashion relative to each other, therebyforming right angles, see FIGS. 8A and 8B. While the figures illustratea significant spacing between the individual horizontal and/or verticalelements, the spacing can be decreased in order to form ananti-biofouling structure 20 which has a tightly knit, weaved patternwith little or no spacing in between. In a preferred embodiment, thehorizontally positioned elements 50 and the vertically positionedelements 52, such as fibers, are made of natural or synthetic plastics,but could be made of other materials such as metals, nylons, cotton, orcombinations thereof. The anti-biofouling structure 20 may also beconstructed of a biodegradable material such that continued exposure tothe aquatic environment results in environmentally friendly degradation.Whichever type of materials are used, the anti-biofouling structure 20may be constructed such that the structure is formable such that it iscapable of being expanded three-dimensionally, radially, longitudinally,or combinations thereof. This constriction allows positioning over anobject so that the anti-biofouling structure 20 mirrors the contour ofthe surface of the object for which it is attached thereto.

In order to impart anti-biofouling characteristics, attached to orembedded within the horizontally positioned elements 50 and/or thevertically positioned elements 52 are agents which prevent biofouling.In a preferred embodiment, the anti-biofouling agent is sirolimus havingthe following chemical structure:

Sirolimus, also known as rapamycin, is a macrocyclic triene antibioticoriginally isolated from the soil microorganism streptomyceshygroscopicus. Since first being used as an anti-fungal antibiotic, useof Sirolimus has expanded to other fields of medicine. Sirolimus iscommonly used as a powerful immunosuppressant drug for preventingrejection after organ transplant surgeries. Research also indicates thatSirolimus can act as a cell-cycle inhibitor, blocking the naturalprogression of the cell cycle. Other anti-biofouling agents, such asbiocides, known to one of skill in the art may be used as well, eitherindividually, or in combination. Anti-biofouling agents which preventboth microfouling, such as biofilm formation and bacterial attachment,and macrofouling, such as attachment of large organisms, includingbarnacles or mussels, are preferable.

Referring to FIGS. 7A and 8A, attached to the horizontally positionedelement 50 and the vertically positioned element 52 are strips 54. Thestrips 54 contain various concentrations of sirolimus and areconstructed in such a manner as to leach or diffuse out of the strip 54and into the external environment, thus preventing the various plant andanimal species from attaching or establishing a presence on theanti-biofouling structure 20. FIGS. 7B and 8B illustrate an alternativeembodiment of the anti-biofouling structure 20. The anti-biofoulingstructure 20 has a reservoir 56 which contains free or microencapsulatedsirolimus. The microencapsulation provides a mechanism in which thesirolimus is diffused or released into the environment in a timedependant manner. The sirolimus filled microcapsules 58 can be embeddedinto the horizontally positioned element 50 and the verticallypositioned element 52 without the use of the reservoir 56. While thesemechanisms described above may be the preferred methods for embeddingsirolimus within the anti-biofouling structure 20, other methods ofinserting the anti-fouling agent, such as the use of spray-onapplications, as known to one of skill in the art is contemplated.Additionally, the anti-biofouling structure 20 need not contain thevertical or horizontal elements but may rather be made of a pliablesheet which contains the anti-fouling agent embedded therein. To providea securing mechanism, the anti-biofouling structure 20 can includefastening elements, such as but not limited to loop 62 and hook 64 typefasteners, such as VELCRO, or snaps, buttons, glue strips, or zippers.

The instant invention further contemplates a system for preventingbiofouling of an object stored in an aquatic environment. The systemincludes the anti-biofouling structure as previously described and aprotective enclosure element, which may comprise a material containingone or more anti-biofouling agents. FIG. 9 illustrates a particularembodiment of the protective enclosure element 64 in the form of anexpandable bag. Protective enclosure element 64 has a generally circularshaped front surface 66 and an expandable/collapsible body portion 68. Aportion of the expandable/collapsible body contains accordion-likeinfoldings 70 which allow the protective enclosure element 64 to betraversed between a first resting or collapsed position, see FIG. 9, anda second fully extended position, see FIG. 11, or multiple positionsbetween the first and second positions.

Attached to the protective enclosure element 64 is a first cable 72 anda second cable 74. The first cable 72 and the second cable 74 which canbe made of rope, plastic, or preferably of stainless steel, connect viaattaching element 76, such as a clip or swage, to a single securingcable or lanyard 78. When in the extended form, the securing end 80 ofthe protective enclosure element 64 is exposed and secures theprotective enclosure element 64 to a structure or object, such as anexposed shaft of a boat propeller, by way of fastening element 82, seeFIG. 10. Fastening element 82 can be connected to the protectiveenclosure element 64 through a securing string 84. FIG. 11 illustratesan alternative embodiment of the protective enclosure element 64. Thisembodiment contains the same features as described previously; however,the second cable has a coiled portion 86.

FIG. 12 is a perspective view of the fully extended protective enclosureelement 64. As illustrated, the securing end 80 contains the fasteningelements 88 and 90. The fastening elements 88 and 90 are illustrated asa loop and hook type fastener, i.e. VELCRO, however, the fasteningelements may also include snaps, clasps, clip, buttons, zippers, orother fastening type devices known to one of skill in the art. Althoughnot necessary, the securing end 80 may be designed to contain portions92 and 94 which provide a place in which securing end 80 may be attachedto the external aquatic structure.

FIG. 15 illustrates the protective enclosure element 64 in the fullyextended position and placed over the propeller 16. FIG. 16 shows theaddition of the anti-biofouling structure 20 to the propeller 16. Inuse, the protective enclosure element 64 and the anti-biofoulingstructure 20 can be secured to the necessary structures with the aid ofa diver. For example, the diver encapsulates the protective enclosureelement 64 over the propeller 16 by extending the protective enclosureelement 64 from the first storage position to the second extendableposition. The protective enclosure element 64 is secured to the exposedpropeller shaft 18 through the securing element 82, including but notlimited to a gasket such as a closed cell foam ring (not illustrated)and a circlip, see 82′ FIG. 9, commonly used on agriculture equipment.The securing elements can be constructed of plastic or stainless steelmaterials and can be sized to fit specific sized shafts. The protectiveenclosure element 64 may also be designed to seal against itself throughthe use of various sealing methods such as snaps, buttons, or hook andloop fastening systems, such as VELCRO. In a particular embodiment, thesecuring end 80 of the protective enclosure element 64 is sealed withVECLRO type retention strips 88 and 90 which are attached to the outsideperimeter of the protective enclosure element 64. This providesattachment of the protective enclosure element 64 around the propellershaft.

The protective enclosure element 64 may also include a semi-rigid,rectangular plastic stiffening plate 96, see FIG. 13. The stiffeningplate 96 is riveted to the inside of the protective enclosure element64. The plate assists in defining the protective enclosure element 64and will also facilitate the removal process by providing support forthe device that triggers release of the protective enclosure element 64from around the propeller. This balances and facilitates the removal ofthe protective enclosure element 64, thus reducing the likelihood of thedevice becoming ensnared in either the propeller blades or rudderappendages. The circlip 82′, which maintains the protective enclosureelement 64 seal around the propeller shaft 18, may be designed to have alooped portion. The VELCRO which is used to seal the forward end of theprotective enclosure element 64 on both sides of the forward face alsocontains a looped portion. The looped portion can be used to clip thecirclip together. This prevents the VECLRO connection from becomingunattached and secures the circlip. Once secured in place, theprotective enclosure element 64 and the anti-biofouling structure 20,which has been fitted to the propellers 16, remain in place without theneed for continuous monitoring and re-securing steps, thereby protectingthe encapsulated structures from the aquatic environment without anyadditional efforts from the user.

One of the advantages of the system as described herein is that thecomponents of the system are designed for easy removal. The two cables72 and 74 are positioned on the outside surface of the protectiveenclosure element 64 and are fed over the top of the propeller bladeswhen the protective enclosure element 64 is fully extended. The twocables may be positioned at points which are 180 degrees from each otherwhen facing the back side of the propeller. Each of the cables maysimply be attached to the protective enclosure element 64 via stitching,gluing, or through the use of a small diameter, TEFLON-lined syntheticguide tube 98, see FIGS. 10 and 14. The tube can be secured at one ormore points on each side of the outside perimeter of the protectiveenclosure element 64. The tubes can be designed to contain a 90 degreebend with an opening facing the aft and the other end facing thepropeller shaft. The cables 72 and 74 are secured together with theattaching element 76 to form the single securing cable 78. The securingcable 78 is led aft and up over a portion of the boat, such as the swimplatform or transom, and secured to the inside of the boat through acleat on each side of the boat with slight tension. When the boat is atrest, the likelihood that the cable becomes entangled by an object andresults in creating a strong enough tension so as to dislodge thesecuring devices is minimal.

Once the boat operator decides that the protective enclosure element 64must be removed, the operator pulls upon the securing cable 78 with abackward force. Such a force simultaneously pulls on the circlip andreleases the device from the propeller shaft. The backward force alsoreleases the VELCRO connection, thereby releasing the protectiveenclosure element 64. The protective enclosure element 64 is now free tobe pulled completely off the enclosed object, i.e. propeller 16. Oncefree from the propeller, the boat operator can start the engine, therebycreating rotational spin of the propellers. As the propellers rotate,the anti-biofouling sock 20 is expelled from the propellers into thewater. The operator can then simply retrieve the expelledanti-biofouling sock 20 from the water. Alternatively, if theanti-biofouling sock 20 is made of a degradable material, the sock canbe left safely in the water to naturally disintegrate.

FIGS. 17-19 illustrate an alternative embodiment of the anti-biofoulingstructure, illustrated generally as 100. In this embodiment, thestructure 100 is formed from a first rigid member 102 and a second rigidmember 104 interconnected to form a clam-shell configuration. Each ofthe rigid members 102 and 104 contain an interior 106 and 108 which issized and shaped to house a propeller. The outer shell is preferablymade from a material, such as plastics or a natural material, such ascotton, having a hardness to retain its shape. Coated into the plasticor cotton material is one or more anti-biofouling, biocide materials.Alternatively, or in combination, a biocide paint may be used to coatthe outer surfaces 110 and 112. In one embodiment, the bottom edge 114of the first rigid member 102 and the bottom edge 116 of the secondrigid member 104 are hingedly connected through a living hinge 118 and120 or any other hinge mechanism which allows each of the halves to moverelative to each other, thereby opening and closing about the hinge.Each of the rigid members 102 and 104 may further contain a cut-outsection 122 and 124 which are sized and shaped to allow a rotor shaft topass through when placed side by side.

Referring to FIG. 18, when the first rigid member 102 is aligned withthe second rigid member 104, the cut out sections 122 and 124 form anopening 126. When the structure 100 is placed over a rotor, the shaftconnecting to the rotor passes through the opening. To secure the firstrigid member to the second rigid member, the top surface 128 of thefirst rigid member 102 and the top surface 130 of the second rigidmember 104 contain one locking member of a locking mechanism. Asillustrated, the top surface 128 contains an eyelet 132 which ispositioned to align with in a parallel fashion, or overlap, a secondeyelet 134 attached to the top surface of 130 when the two rigid membersare closed together. A securing member, illustrated herein as a cotterpin 136, may be used to secure the two members together. Preferably, thecotter pin 136 is secured to a portion of a lanyard 138. A secondportion of the lanyard 138 is attached to either half of the clam shellhalves. As shown in FIG. 18, the lanyard 138 attaches to the bottomsurface area 140 of the first half 102 or the bottom surface 142 of thesecond half 104 through, for example, an eyelet 144. The amount oflanyard which attaches to the cotter pin 136 is preferably less than theamount of lanyard used to attach to the bottom. In this manner, pullingon the handle attached to the lanyard 138 results in pulling the pin 136from the overlapping eyelets 132 and 134 first. As the lanyard 138 iscontinually pulled back, at some point a tension is formed on the partof the lanyard that is connected to either of the rigid members 102 or104, resulting in the pulling apart of one or both of the rigid members102 and 104. Although not illustrated, each of the halves may contain aweighted section to allow them to sink below the boat. Since they remainattached to the lanyard, the user can simply retrieve the halves bypulling on the lanyard 138. Alternative securing mechanisms, includingbuttons, snaps, zippers or other means known to one of skill in the artcan be used as well.

Referring to FIGS. 20-22, an alternative embodiment of theanti-biofouling structure is shown and illustrated as a bag-like cover146. The bag-like cover 146 is preferably made of a pliable plastic ornatural fiber material which is impregnated, encapsulated, or coatedwith a biocide material. The bag-like cover 146 contains two panels 148and 150, see FIGS. 20 and 21. Panel 148 contains a face 152 which formsthe front portion of the bag-like cover 146 and an edge 154 whichtraverses the perimeter of the face 152. The panel 150 contains a face156 which forms the back portion of the bag-like cover 146. An edge 158traverses the perimeter of the face of 156. The panels 148 and 150interconnect through edges 154 and 158 to form an interior portion 160.The interior portion 160 is sized and shaped to receive a structure,such as a boat propeller, which needs to be protected from the effectsof biofouling. Preferably, the two panels 148 and 150 are partiallyinterconnected through a fastening mechanism, such as stitching 162 orchemical means.

As illustrated in FIG. 21, a portion of the bag-like cover 146 does notprovide for the panels 148 and 150 to be interconnected by stitching162. This configuration provides for an opening 164. The opening 164provides a means for the bag-like cover 146 to be arranged over astructure or object which needs to be protected from biofouling. Oncesecured over the object, bag-like cover 146 can be closed throughsecuring members such as buttons, snaps, zippers, or other means knownto one of skill in the art. In a preferred embodiment, the securingmembers are preferably a loop and hook type fastening system, i.e.VELCRO. Accordingly, a portion of the edges 154 and 158 or the faces 152and 156 may contain the VELCRO loops 166 secured through, for examplestitching or chemical fastening, their surfaces. An externally attachedstrap containing VELCRO hooks is used to fasten the edges 154 and 158together. By placing edges 154 and 158 in close proximity, the strap 168containing the VELCRO hooks is placed over the VELCRO loops 166portions, see FIG. 22.

As illustrated in FIG. 21, the back face 156 contains a slitted portion170 which terminates in a portion of the bag which extends outwardlyfacing cylindrical shape 172. The slitted portion 170 provides for thebag-like cover to enclose an object which contains portions which maynot need to be covered. For example, the cylindrical shape 172 shown inFIG. 21 is designed to allow the bag-like cover 146 to enclose thepropeller of the boat but allow the propeller shaft 174 to extend out.The portions of the face 156 that defines the slitted areas can becovered with VELCRO loops as described above. Aligning the areas inclose proximity allows a second strap 176 containing VELCRO hooks to beplaced on top to secure them together around the circumference of thepropeller shaft 174. Each of the straps 168 and 176 may contain one ormore attached O-rings (not illustrated). One or more lanyards (notillustrated) may be attached to the O-rings. Pulling the lanyards awayfrom the cover provides a force that results in removal of the straps168 and 176 from the VELCRO loops 166. Fastened to the interior portionof the cover 146 may be one or more D-rings (not illustrated) whichpreferably attach to one or both straps 168 and 176 through, forexample, stitching. Once coupled to the D-rings, the straps 168 and/or176 remain connected to the bag thereby reducing the risk that they willbe displaced. One or more openings along the surface of the bag may beutilized to allow the straps to exit the interior portion and couple tothe VELCRO loops 166. Once the straps are removed from the VELCRO loops166, the bag is partially opened and it can be removed from covering theobject.

Referring to FIGS. 23-25, an alternative embodiment of theanti-biofouling structure is shown and illustrated as bag 178. The bag178 is preferably constructed of a collapsible plastic material, similarto a standard garbage bag, and is impregnated or coated with a biocidematerial. The bag 178 contains a main body comprising an opening whichis sized and shaped to allow a structure to be stored within theinterior portion 184. The outer edges 186 and 184 may be made of astronger material than that of the body to allow the bag 178 to maintainsome shape. Tightening members, illustrated herein as drawstring 190 and192, are used to enclose the bag 178 over the object. Drawstring 190 and192 are preferably constructed in such a manner that, as the firstdrawstring 190 is pulled toward the second drawstring 192, opening 182is reduced. Additionally, the drawstring 190 and 192, when pulledtogether maintain a tension so that when they are not secured together,they retract back to their original, non-pulled state. The drawstrings190 and 192 contain eyelets 194 and 196 which align together when thetwo drawstrings are pulled toward each other. A securing member, such asa cotter pin 198 is used to secure the drawings together. In a similarmanner, as described before, the cotter pin 198 can be secured to astring 200. The opposite end of the string 200 may be attached to thebag 178 at a canvas strap 202. Pulling on the canvas strap 202 resultsin dislodging the cotter pin 198 from the eyelets 194 and 196. Once theeyelets are no longer secured to each other, the drawstrings 190 and 192retract, opening the bag and exposing object, illustrated herein, as aboat propeller 204, see FIG. 25.

All patents and publications mentioned in this specification areindicative of the levels of those skilled in the art to which theinvention pertains. All patents and publications are herein incorporatedby reference to the same extent as if each individual publication wasspecifically and individually indicated to be incorporated by reference.

It is to be understood that while a certain form of the invention isillustrated, it is not to be limited to the specific form or arrangementherein described and shown. It will be apparent to those skilled in theart that various changes may be made without departing from the scope ofthe invention and the invention is not to be considered limited to whatis shown and described in the specification and any drawings/figuresincluded herein.

One skilled in the art will readily appreciate that the presentinvention is well adapted to carry out the objectives and obtain theends and advantages mentioned, as well as those inherent therein. Theembodiments, methods, procedures and techniques described herein arepresently representative of the preferred embodiments, are intended tobe exemplary and are not intended as limitations on the scope. Changestherein and other uses will occur to those skilled in the art which areencompassed within the spirit of the invention and are defined by thescope of the appended claims. Although the invention has been describedin connection with specific preferred embodiments, it should beunderstood that the invention as claimed should not be unduly limited tosuch specific embodiments. Indeed, various modifications of thedescribed modes for carrying out the invention which are obvious tothose skilled in the art are intended to be within the scope of thefollowing claims.

What is claimed is:
 1. An anti-biofouling structure for placement ontoan object exposed to aquatic environments comprising: a pliable sheetmaterial formed from a plurality of interwoven fibers to form alattice-like configuration for securing to said object, said pliablesheet material being fenestrated to allow passage of at least some ofsaid aquatic environment therethrough, said pliable sheet materialincluding at least one anti-biofouling agent embedded within saidpliable sheet material, said biofouling agent comprising rapamycin,whereby said pliable sheet material is securable about said object toreduce the formation of biofouling organisms along the surface of saidobject.
 2. The anti-biofouling structure for placement onto an objectexposed to aquatic environments according to claim 1 wherein saidanti-biofouling agent is microencapsulated.
 3. The anti-biofoulingstructure for placement onto an object exposed to aquatic environmentsaccording to claim 1 wherein said anti-biofouling agent is adapted tosubstantially kill bio-fouling organisms passing through saidfenestrations.
 4. The anti-biofouling structure for placement onto anobject exposed to aquatic environments according to claim 1 wherein saidanti-biofouling agent is embedded into a binder and coated onto saidpliable sheet material.
 5. The anti-biofouling structure for placementonto an object exposed to aquatic environments according to claim 4wherein said pliable sheet material is in the form of a mesh.
 6. Theanti-biofouling structure for placement onto an object exposed toaquatic environments according to claim 1 wherein said pliable sheetmaterial includes at least one securing member.
 7. The anti-biofoulingstructure for placement onto an object exposed to aquatic environmentsaccording to claim 1 wherein said pliable sheet material is formed intoa bag shaped to enclose one or more blades of a boat propeller, toreduce formation of biofouling on an outer surface of said blades. 8.The anti-biofouling structure for placement onto an object exposed toaquatic environments according to claim 7 wherein said pliable sheetmaterial is biodegradable.
 9. The anti-biofouling structure forplacement onto an object exposed to aquatic environments according toclaim 7 wherein said pliable sheet material is made of a natural fiber,synthetic fiber, plastics, or combinations thereof.
 10. A system forreducing biofouling of objects which are exposed to aquatic environmentscomprising: a bag cover formed from a pliable fenestrated sheet materialhaving one or more anti-biofouling agents embedded therein, saidbiofouling agent comprising rapamycin, said cover having a plate memberfront surface, an expandable body portion being secured thereto andtraversable between a first position and a second expanded position, aninterior portion sized and shaped to enclose an object which is exposedto an aquatic environment, and one or more securing members for securingsaid cover to said object.
 11. The system for reducing biofouling ofobjects which are exposed to aquatic environments according to claim 10wherein said cover is secured to a securing cable, whereby applying aforce to said securing cable results in releasing said securing membersand removal of said cover from said object.
 12. The system for reducingbiofouling of objects which are exposed to aquatic environmentsaccording to claim 11 wherein said securing cable contains twoadditional cables, said additional cables being separated by apredetermined distance.
 13. The system for reducing biofouling ofobjects which are exposed to aquatic environments according to claim 12wherein said cables are attached to said cover through use of a guidetube.
 14. The system for reducing biofouling of objects which areexposed to aquatic environments according to claim 13 wherein one ofsaid additional cables is coiled.
 15. The system for reducing biofoulingof objects which are exposed to aquatic environments according to claim14 wherein said object is a propeller.
 16. The system for reducingbiofouling of objects which are exposed to aquatic environmentsaccording to claim 10 wherein said anti bio-fouling agent ismicroencapsulated for timed release of said anti bio-fouling agent. 17.A system for reducing biofouling of objects which are exposed to aquaticenvironments comprising: a cover assembly, said cover assemblycontaining a first face member connected to a second face member with awoven sheet material, said woven sheet material containing ananti-biofouling agent embedded therein, said biofouling agent comprisingrapamycin, an interior portion of said cover assembly sized and shapedto receive a boat propeller, said second face member containing aslitted portion terminating in an opening, said opening sized and shapedto receive a shaft of said propeller, said first face member and saidsecond face member each including a first part of a hook and loopfastener, a strap assembly, said strap assembly including a second partof a hook and loop fastener, said second part of said hook and loopfastener removably securable to said first part of said hook and loopfastener on said first face member and said second face member to securesaid cover assembly in a closed position, said strap assembly havingsufficient length to extend from said propeller to a position within thewatercraft to which said propeller is secured.
 18. The system forreducing biofouling of objects which are exposed to aquatic environmentsaccording to claim 17 wherein said strap assembly further is coupled toone or more cables whereby applying a force to said cables removes saidstrap assembly from said first part of a hook and loop fastener.
 19. Thesystem for reducing biofouling of objects which are exposed to aquaticenvironments according to claim 17 wherein said cover assembly isconstructed from cotton, plastic, or combinations thereof.
 20. Thesystem for reducing biofouling of objects which are exposed to aquaticenvironments according to claim 17 further comprising a formable meshsheet covering material for securing to at least one blade of saidpropeller, said formable mesh sheet covering material containing atleast one anti-biofouling agent embedded therein.